syzbot

sched: DL replenish lagged too much
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (2 ticks this GP) idle=6ab4/1/0x4000000000000000 softirq=16384/16384 fqs=0
rcu: 	(detected by 0, t=10502 jiffies, g=12261, q=1629 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 60 Comm: kworker/u8:4 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:141 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:172 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:191 [inline]
RIP: 0010:kasan_check_range+0x65/0x2c0 mm/kasan/generic.c:200
Code: 00 00 00 00 00 00 00 ff f3 0f 1e fa 4c 39 cf 0f 82 58 02 00 00 49 89 ff 49 c1 ef 03 49 ba 00 00 00 00 00 fc ff df 4f 8d 1c 17 <49> ff c8 4d 89 c1 49 c1 e9 03 48 bb 01 00 00 00 00 fc ff df 4d 8d
RSP: 0018:ffffc90000a08b08 EFLAGS: 00000806
RAX: 00000000ffffff01 RBX: ffffffff99846fe0 RCX: ffffffff819ca442
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff99846fe0
RBP: ffffc90000a08bf0 R08: ffffffff99846fe4 R09: ffff800000000000
R10: dffffc0000000000 R11: fffffbfff3308dfc R12: ffffffff99846ff0
R13: ffffffff99846fe8 R14: 1ffffffff3308dfe R15: 1ffffffff3308dfc
FS:  0000000000000000(0000) GS:ffff888126478000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000600 CR3: 000000000db36000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
 atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1300 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:111 [inline]
 do_raw_spin_lock+0x112/0x290 kernel/locking/spinlock_debug.c:116
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
 _raw_spin_lock_irqsave+0xb3/0xf0 kernel/locking/spinlock.c:162
 debug_object_deactivate+0x9a/0x250 lib/debugobjects.c:873
 debug_hrtimer_deactivate kernel/time/hrtimer.c:443 [inline]
 debug_deactivate+0x1d/0x200 kernel/time/hrtimer.c:483
 __run_hrtimer kernel/time/hrtimer.c:1745 [inline]
 __hrtimer_run_queues+0x2b0/0xc60 kernel/time/hrtimer.c:1841
 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
 __sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1058
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
 sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:folio_nid include/linux/mm.h:1592 [inline]
RIP: 0010:folio_pgdat include/linux/mm.h:1817 [inline]
RIP: 0010:folio_zone include/linux/mm.h:1822 [inline]
RIP: 0010:zone_stat_mod_folio include/linux/vmstat.h:432 [inline]
RIP: 0010:__folio_start_writeback+0x80d/0xa60 mm/page-writeback.c:3068
Code: 43 80 3c 2f 00 0f 85 8e fe ff ff e9 91 fe ff ff e8 e8 e1 c4 ff e8 63 b0 3e 09 4d 85 f6 74 d5 e8 d9 e1 c4 ff fb 48 8b 44 24 10 <42> 80 3c 28 00 74 08 48 89 df e8 24 86 2a 00 4c 8b 3b 4c 89 f8 48
RSP: 0018:ffffc9000211ea20 EFLAGS: 00000293
RAX: 1ffffd40003b2320 RBX: ffffea0001d91900 RCX: ffff88801bfd0000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000211eb78 R08: ffffffff8f5c2237 R09: 1ffffffff1eb8446
R10: dffffc0000000000 R11: fffffbfff1eb8447 R12: ffffea0001d91908
R13: dffffc0000000000 R14: 0000000000000200 R15: 0000000000000000
 ext4_bio_write_folio+0xebb/0x1f20 fs/ext4/page-io.c:583
 mpage_map_and_submit_buffers fs/ext4/inode.c:2324 [inline]
 mpage_map_and_submit_extent fs/ext4/inode.c:2514 [inline]
 ext4_do_writepages+0x1d43/0x4610 fs/ext4/inode.c:2931
 ext4_writepages+0x205/0x350 fs/ext4/inode.c:3025
 do_writepages+0x32e/0x550 mm/page-writeback.c:2604
 __writeback_single_inode+0x145/0xff0 fs/fs-writeback.c:1719
 writeback_sb_inodes+0x6c7/0x1010 fs/fs-writeback.c:2015
 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2086
 wb_writeback+0x44f/0xaf0 fs/fs-writeback.c:2197
 wb_check_old_data_flush fs/fs-writeback.c:2301 [inline]
 wb_do_writeback fs/fs-writeback.c:2354 [inline]
 wb_workfn+0xaef/0xef0 fs/fs-writeback.c:2382
 process_one_work kernel/workqueue.c:3263 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3346
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
 kthread+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g12261 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=6460
rcu: rcu_preempt kthread starved for 10502 jiffies! g12261 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:I stack:26888 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:7026
 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
 kthread+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>